taxonID	type	description	language	source
195F3D4A4BC65BCEBA579BCA1C204527.taxon	description	Morphological description. The frustule is drum-shaped, the valve is flat or slightly concave or convex (Fig. 3 D-H). Valve diameter 13.6 - 26.2 μm, height 3.4 - 5.2 μm. Areolae are arranged into sectors. The external openings of the process (4 - 6) are clearly visible on the curved outer surface the mantle (Fig. 3 F, H). The pseudonodulus is located above the openings of the rimoportulae, it has a slight depression. According to Hasle (1977), there are no significant taxonomic differences between A. normanii f. subsalsus and the nominate form (the ranges of valve diameters coincide), but there may be ecological preferences. Krammer and Lange-Bertalot (2000) did not identify forms, but gave so-called morphotypes that do not have a rank in nomenclature and, according to their data, in the A. normanii population from the Rhine region, a continuous range of forms was observed during the life cycle. Kozyrenko et al. (2008) synonymized A. normanii f. subsalsus with the nominate form and we adhere to their point of view.	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
195F3D4A4BC65BCEBA579BCA1C204527.taxon	distribution	Distribution. Actinocyclus normanii is found sporadically in epilithic benthic samples from the the Southern Bug River at the three investigated stations (Table 1). It has previously been recorded for Ukrainian water bodies, especially for the Steppe zone noted in the monograph (Tsarenko et al. 2009) and for the Dnipro-Bug Estuary in particular (Vladimirova 1971; Zhukinskiy et al. 1989). It may travel upstream with highly mineralized waters from the estuary and appear near Mykolaiv City. Upstream occurrences have been documented for Actinocyclus normanii f. subsalsus for Germany. According to diatom core analyses, this taxon reached the River Havel around 1900 (Schoenfelder 1997). It was missing in Berlin (which is situated more than 200 km inland from the North and Baltic Seas) in the 1830 s- 1850 s (Jahn and Kusber, unpubl. data from the Ehrenberg collection at BHUPM) but occurred in recent samples at the beginning of the 20 th century (Kolbe 1925; Geissler and Kies 2003) where it became an established part of the flora (Geissler and Kies 2003; Geissler et al. 2006). It was discussed by Schoenfelder (1997) that a prerequisite for naturalisation might be the anthropogenically induced increase of salinity over the minimum value of salt tolerance. In other inland waters, e. g in the Czech Republic, the taxon occurred but did not establish (Frankova-Kozakova et al. 2007). Additionally, it is a widely distributed species occurring in Europe, North and South America, the islands of the Atlantic Ocean, Africa, Asia, Australia, and New Zealand (Guiry and Guiry 2021). However, the species was considered invasive for Russia (see Kastovsky 2010; Korneva 2014) but was not included in the Handbook of alien species in Europe, outcome of the DAISIE (Delivering Alien Invasive Species Inventories for Europe) project (Handbook of alien species in Europe DAISIE 2009).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
89E297358E805FAE8A899FCEF001308E.taxon	description	Morphological description. Frustule cylindrical, valve face flat with randomly located areolae, diameter is 13.2 - 14.4 μm (Fig. 3 A). Curve of the valve with longitudinal areolae (12 - 14 in 10 μm) and transverse curly rows of areolae. The ringleiste is wide, connective spines are small-sized, sharp-ended, tear-drop-shaped or branched.	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
89E297358E805FAE8A899FCEF001308E.taxon	distribution	Distribution. This species was observed in all sampling sites and is the first confirmed record for the whole basin of the Southern Bug River (Table 1). In the mid- 1930 s Swirenko (1941) found this species as Melosira islandica var. helvetica O. Mueller in the lower part of the River starting from Mygea rapids and some other lower stations along the River bed to the mouth (Swirenko 1941). Aulacoseira islandica occurs in the Dnipro River basin and its reservoirs (Tsarenko et al. 2009). It is also a common species for Europe (Bulgaria, Iran, Finland, Germany, Lithuania, Romania, Russia, Sweden, Ukraine), Asia (Georgia, Russia, Turkmenistan), North America (Canada, Greenland, USA); Barents, Bering and White Seas (Tsarenko et al. 2009).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
1ACFE8F899EB591B97F96551749199D7.taxon	description	Morphological description. Cells cylindrical, valve face flat, 7.5 - 12.8 μm in diameter, valve mantle 3.8 - 4.7 μm high. Valve face with rough areolae, located in intersecting diagonal rows (Fig. 3 B).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
1ACFE8F899EB591B97F96551749199D7.taxon	distribution	Distribution. At the localities of upstream Mykolaiv, in Mykolaiv City and downstream Mykolaiv Aulacoseira nivalis is the first record for Ukraine (Table 1). As for other countries, it is known from alpine and northern regions (Krammer and Lange-Bertalot 2000); frequently occurring in western North America (English and Potapova 2009) and as being abundant in lake sediments in Brazil.	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
07D5A7448BC8527F82757BDF62DB5426.taxon	description	Morphological description. Frustules are usually low to high-cylindrical, valve face flat. Valve is 16.6 μm in diameter, 4.4 μm high, number of areolae lines on valve bend 15 in 10 μm, in the line 18 areolae in 10 μm. Ringleiste is wide, linking spines are large, sharpened (Fig. 3 C).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
07D5A7448BC8527F82757BDF62DB5426.taxon	distribution	Distribution. Occurred in the Southern Bug River in Mykolaiv city (near Varvarivskyi Bridge) (Table 1). This species is known from the Dnipro River basin (Tsarenko et al. 2009). Aulacoseira subarctica is widely distributed across Europe (Germany, Great Britain, Holland, Norway, Russia, Ukraine, Scandinavia), Asia (Russia, Japan, China), North America, Australia and New Zealand. The species is rare in the tropics, and positive identifications are lacking for Africa (Chris et al. 2003).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
AC3606D4CFAB50B7A11B1C57677A76DB.taxon	description	Morphological description. The frustule has the form of a drum, valves are almost flat, diameter 24.4 - 26.6 μm, 8 - 10 marginal processes in 10 μm, 2 - 5 central processes (Fig. 4 E).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
AC3606D4CFAB50B7A11B1C57677A76DB.taxon	distribution	Distribution. This centric taxon appeared at the Mykolaiv site in the Southern Bug River; for Ukraine it was mentioned for the first time in our previous investigation (Table 1; Genkal and Bilous 2015), afterwards it was found in the tributaries of Dnipro in eastern and central parts of the country (Berezovskaya 2019; Kryvosheia and Kapustin 2019). This is a widely distributed species: Europe, Asia, America (North and South), Africa, Australia and New Zealand; it was even found in Lake Baikal, also in the oceans over the world (Stachura-Suchoples and Kulikovskiy 2014; Genkal et al. 2020).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
234670D8EEC55695B332182837CBF9B3.taxon	description	Morphological description. The frustule is disciform, valve face concentrically undulate, 13.6 - 21 μm in diameter, striae multiseriate with 9 - 12 areolae in 10 μm, ribs continue on the curve of a valve, spines grow from each rib (Fig. 7 G).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
234670D8EEC55695B332182837CBF9B3.taxon	distribution	Distribution. This species was found above Mykolaiv city in the Southern Bug River bed (Table 1). From Ukrainian territory, it is known from the Dnipro River, the Dnipro-Bug Estuary (Topachevsky and Oksiyuk 1960; Vladimirova 1971) and the Danube River (Tsarenko et al. 2009). Cyclostephanos dubius is a cosmopolitan species, recorded for Berlin, Germany (Geissler and Kies 2003) and further sites in Europe (Hungary, Dania, Estonia, Moldova, Russia, Ukraine), Asia (Georgia, Russia, Uzbekistan), North America (Canada, USA), Africa (Egypt); Baltic and White Seas (Tsarenko et al. 2009; Kiss et al. 2012; Genkal et al. 2020).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
91130038E4C65C9681F0A2DF63C16419.taxon	description	Morphological description. Frustule disciform, valve face flat, 9.4 - 14.5 μm in diameter, multiseriate striae 10 - 14 in 10 μm, ribs are continuing on curve of the valve, spines grow from every rib (Fig. 7 H).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
91130038E4C65C9681F0A2DF63C16419.taxon	distribution	Distribution. C. invisitatus was found 5 km downstream Mykolaiv city (Table 1), and was recorded for this River earlier (Bilous et al. 2012; Bilous et al. 2014; Belous 2016). In turn, it is common for the Dnipro River and there are some findings in the Danube River (Tsarenko et al. 2009). Probably a cosmopolitan species, known from Europe (Germany, Hungary, Poland, Russia), Asia (Armenia, Azerbaijan, Russia), Northern America (USA), Africa (Egypt); Caspian Sea (Wojtal and Kwandrans 2006; Tsarenko et al. 2009; Kiss et al. 2012; Genkal et al. 2020).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
8A17A8A89F4C5C1D866045680D1A8083.taxon	description	Morphological description. Frustule low-cylindrical, central part of the valve is slightly tangentially undulated, 3.6 - 5.6 μm in diameter, clear boundary between regional and central zones absent, 10 - 15 striae in 10 μm, and a central process (Fig. 6 B, C).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
8A17A8A89F4C5C1D866045680D1A8083.taxon	distribution	Distribution. Valves were found at all investigated sites of the Southern Bug during this research (Table 1). For Ukrainian territory, it has been reported for the Dnipro River (Maystrova et al. 2007). In general, Cyclotella atomus is a cosmopolitan species (Krammer and Lange-Bertalot 2000), widespread in freshwater and marine environments in North America, Europe, and Asia, and has also been recorded from Argentina and South Africa (Poulickova 1993; Medioli and Brooks 2003; Tanimura et al. 2004; Yang et al. 2005; Wojtal and Kwandrans 2006; Genkal et al. 2020).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
FC8618A4C300549FA0FB42B068B05478.taxon	description	Morphological description. The frustule is low-cylindrical, central part of valve is slightly tangentially undulated, valves 4.6 - 7 μm in diameter, and a clear boundary between regional and central zones is present, 15 - 20 wedge-shaped striae in 10 μm, with central process (Fig. 6 D, E).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
FC8618A4C300549FA0FB42B068B05478.taxon	distribution	Distribution. Cyclotella atomus var. gracilis is here first reported for the studied area, and was found at all investigated sites during this study (Table 1). In turn, its existence was reported in Dnipro waters (Maystrova et al. 2007), as well as for the Danube River (Genkal and Ivanov 1990). This species is cosmopolitan, i. a. it was recorded for European waters (Kiss et al. 2012; Genkal et al. 2020).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
A1B2DA94A46C513BAF59405D68801B1A.taxon	description	Morphological description. Frustule low-cylindrical, central part of valve tangentially undulated, valves 9.1 - 12.3 μm in diameter, 12 - 14 striae in 10 μm, 1 - 4 central fultoportulae, 6 marginal fultoportulae in 10 μm (Fig. 6 G).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
A1B2DA94A46C513BAF59405D68801B1A.taxon	distribution	Distribution. It was recorded for the first time in Ukraine in our previous investigation near Mykolaiv city of the Southern Bug River and this study confirms its existence in Mykovaiv city and at the downriver sites (Table 1). Cyclotella choctawhatcheeana was recorded as a cosmopolitan species. Its presence has been confirmed in different localities around the world in brackish waters and rivers connected with saline lakes (Prasad et al. 1990). It was found as a component of the phytoplankton in the saline Mexican lake Alchichica (Oliva et al. 2008), in the Baltic Sea, with salinity between 3 and 11 ‰ (Wendker 1991; Hakansson et al. 1993), and the Salton Sea, with a salinity in excess of 40 ‰ (Lange and Tiffany 2002). Additionally, it is known from saline lakes in North America and Africa (Carvalho et al. 1995), reservoirs in Russia (Genkal et al. 2020).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
644DEB0656205EB487DC05FC7DCF59F7.taxon	description	Morphological description. Frustule cylindrical, the medium part of a valve slightly tangentially undulated, or flat, valve diameter is 6.4 - 6.7 μm, a clear boundary between edge and central zone is absent, striae wedge-shaped, 8 in 10 μm, single central fultoportula (Figs 6 H, 7 A).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
644DEB0656205EB487DC05FC7DCF59F7.taxon	distribution	Distribution. Valves were identified at the site in the south of Mykolaiv city in the Southern Bug River (Table 1). It is a widespread species, recorded for Europe, North America, and Asia (Mills et al. 1993; Guiry and Guiry 2021).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
4ACFEC91171555BDA2671C6BA0DA6759.taxon	description	Morphological description. Frustule low-cylindrical, valve diameter is 3.2 - 3.9 μm, a clear boundary between edge and central zone is absent, striae wedge-shaped, 18 - 20 in 10 μm, central process is absent (Fig. 7 B).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
4ACFEC91171555BDA2671C6BA0DA6759.taxon	distribution	Distribution. C. marina is found in epilithic benthic samples at all investigated sites during this research for the Southern Bug River (Table 1). For Ukrainian territory it is also reported from Khmelnytskyy NPS, (Genkal et al. 2012) and in phytoplankton in Odessa Bay of the Black Sea (Genkal and Terenko 2014). It is also a common species for Europe, North America, and Asia (Ake-Castillo et al. 2012; Genkal et al. 2012; Guiry and Guiry 2021).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
63DA2B6171D15D5687E0F84A27FE4B60.taxon	description	Morphological description. Frustule low-cylindrical, central part of valve is slightly tangentially undulated or flat, valves 5.8 - 9.4 μm in diameter, striae wedge-shaped, 6 - 9 in 10 μm, central process is absent (Fig. 7 C, D).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
63DA2B6171D15D5687E0F84A27FE4B60.taxon	distribution	Distribution. This taxon is sporadically found in epilithic benthic samples from the Southern Bug River at two investigated stations (in Mykolaiv City and downstream Mykolaiv) (Table 1). For other Ukrainian waters it has been reported for the Dnipro River (Maystrova et al. 2007), the Danube River (Genkal and Ivanov 1990). Globally, this taxon is distributed in the Boreal zone, Europe, Asia and North America (Genkal 2014; Genkal et al. 2020).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
78ABD88973645856B1F009A6FBE38C22.taxon	description	Morphological description. Frustule cylindrical, valves with a tangentially undulated central part, 10.4 - 33.3 μm in diameter, striae wedge-shaped 5 - 8 in 10 μm. Central processes (usually from 1 to 9) and spines are present at the mantle of the valve (Fig. 7 E, F).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
78ABD88973645856B1F009A6FBE38C22.taxon	distribution	Distribution. Valves were found at all investigated sites of Southern Bug during this research (Table 1). For Ukrainian territory it has been reported for the Dnipro Estuary, the Southern Bug as well, but near Vinnitsya (300 km upriver form Mykolayiv), the rivers Siverskyi Donets, Dnister, Danube, Dnipro, Desna, Prypiat, Teteriv, Oskol, small rivers in Odessa region and other rivers (Tsarenko et al. 2009). Concerning global distribution, Cyclotella meneghiniana is considered a widespread taxon (Houk et al. 2010); it was also recorded for Berlin, Germany (Geissler and Kies 2003).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
BC68D1C9F0405D348E5F1E436D20D327.taxon	description	Morphological description. Frustule shape is cylindrical to approximately octagonal (Fig. 2 A, F). Valve 12.5 - 26 μm in diameter, mantle height 3.1 - 8.5 μm. Valve face nearly octagonal with flat tops (Fig. 2 B-E, G). Girdle with puncta forming straight and transverse rows 32 - 56 in 10 μm.	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
BC68D1C9F0405D348E5F1E436D20D327.taxon	distribution	Distribution. Melosira subglobosa is one of the most common species at the sampling sites near the Mykolaiv area in the Southern Bug River (Table 1). For Ukrainian territory, it is known from the coastal zone in the northwestern part of the Black Sea, Crimean seaboard, and some estuaries. For a worldwide distribution, it was recorded from coastal zones of Europe, and Asia; specifically, from Lake Aral, Baltic, Bering, Black, Caspian, Mediterranean, North and Norway Seas (Tsarenko et al. 2009).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
CD1BB2E304B25DF39ECF47CA39D59AC4.taxon	description	Morphological description. Frustule is cylindrical, valve flat, 15.7 - 46.6 μm in diameter with numerous small-scale granules, 5.7 - 15.5 μm high (Fig. 2 H).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
CD1BB2E304B25DF39ECF47CA39D59AC4.taxon	distribution	Distribution. Valves were found near Mykolaiv city in the Southern Bug River in our previous sampling study (Table 1; Genkal and Bilous 2015). In Ukraine, it is known from the Southern Bug and lakes in the basins of the rivers Danube, Dnister, Siverskyi Donets, Desna, Prypiat, Dnipro and its reservoirs and estuary. On the global level, it is a widely distributed taxon, known from Europe (i. e. Berlin, Germany, see Geissler and Kies 2003), Russia (Genkal et al. 2020), Asia (Iran), North America (Canada, USA), Africa (Egypt, RSA); Adriatic, Aral, Azov, Baltic, Barents, Black, Caspian, Kara, Mediterranean, North and Red Seas, and throughout North America (Stoermer and Julius 2003). It is also very common in Brazilian waters (Stoermer and Julius 2003; Tremarin et al. 2009; Nardelli et al. 2016).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
E8CC21D03F1A52259F248FF5A667C776.taxon	description	Morphological description. The frustule is cylindrical, valve flat, diameter 3.8 - 4.9 μm, areolae polygonal, in quantities 25 in 10 μm, near centre of a valve, the central process and rimoportula are located (Figs 4 H, 5 A).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
E8CC21D03F1A52259F248FF5A667C776.taxon	distribution	Distribution. Valves were found in benthic samples in Mykolaiv city of the Southern Bug River and downriver (Table 1). For Ukrainian territory it was recorded for estuaries of the Black Sea and nearshore regions (Tsarenko et al. 2009; Genkal and Terenko 2014). Minidiscus proschkinae is widely distributed across estuaries and seacoasts of Europe (Germany, Great Britain, Netherlands, Russia, Ukraine), Asia (Azerbaijan, China), Argentina; Azov Sea, Baltic Sea, Caspian Sea (Park et al. 2017 a).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
4A87A68D2A7D5446B99CF1FF014E0585.taxon	description	Morphological description. The frustule is cylindrical, valves are elliptical-rounded-oval, with diameter 39 - 61 μm, 15 - 17 areolae in 10 μm (Fig. 4 A-D).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
4A87A68D2A7D5446B99CF1FF014E0585.taxon	distribution	Distribution. Valves were found in benthic samples in the Mykolaiv city of the Southern Bug River and downriver (Table 1). For Ukrainian territory it was recorded for estuaries of the Black Sea, also reported for the Southern Bug River (Tsarenko et al. 2009). Pleurosira laevis is quite cosmopolitan, distributed in the Boreal, near coasts of Europe (Czech Republic, Finland, Germany, Romania, Russia, Sweden, Ukraine), Asia (Korea, Turkey), South America (Brazil), Africa (Egypt), Hawaiian Islands; Azov, Black and Marmora Seas (Tsarenko et al. 2009; Park et al. 2017 b). For Europe this taxon is considered an invasive species (Handbook of alien species in Europe DAISIE 2009). An upstream colonisation of Pleurosira laevis with help of different vectors for the River Labe was discussed by Frankova-Kozakova et al. (2007).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
C11EEE8559855D70926728DEB02E1993.taxon	description	Morphological description. The frustule is cylindrical, valves are flat or slightly convex, diameter 7.8 - 12.7 μm (Fig. 5 B). Frustules are connected with marginal flat-spoon fultoportulae providing a very close connection between valve mantles (Fig. 5 C, D).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
C11EEE8559855D70926728DEB02E1993.taxon	distribution	Distribution. This taxon was found at the site of Mykolaiv city in the Southern Bug River (Table 1). Skeletonema subsalsum is widely distributed in Ukrainian waters, known from the Dnipro River in its freshwater reservoirs, in estuaries connected to the Black Sea and from coastal waters of different river basins as well as Crimea coast. It is a cosmopolitan species, known from the Boreal, Europe (Finland, Germany, Ireland, Italy, the Netherlands, Romania, Russia, Sweden, Ukraine), North America (Canada, USA); Baltic, Black and Caspian Seas. (Gibson et al. 1993; Krammer and Lange-Bertalot 2000; Tsarenko et al. 2009; Genkal et al. 2020).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
D62072E20FAA52A1B0EA8932B895C2DC.taxon	description	Morphological description. The frustule is low-cylindrical, valves flat 13.6 - 21.4 μm in diameter, striae multiseriate with 6 - 7 in 10 μm, central processes are absent, spines large and pointy, growing from each rib (Fig. 5 E).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
D62072E20FAA52A1B0EA8932B895C2DC.taxon	distribution	Distribution. Stephanodiscus hantzschii was identified for the Southern Bug River in Mykolaiv city and downstream (Table 1). It is widespread taxon in Ukrainian water bodies: the rivers Danube, Dnister, Southern Bug, Siverskyi Donets, Dnipro and its reservoirs, coastal waters. It is a cosmopolitan species, known from Europe (Belarus, Bulgaria, Finland, France, Germany, Moldova, Norway, Romania Russia, Ukraine), Asia (Armenia, China, Georgia, Japan, Korea, Mongolia, Russia, Tadjikistan, Uzbekistan), North America (Canada, USA); Aral, Azov, Baltic, Black and Caspian Seas (Krammer and Lange-Bertalot 2000; Tsarenko et al. 2009; Genkal et al. 2020).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
F7849DE942DC53DAABB276945D6B1C0C.taxon	description	Morphological description. Frustule disciform, valve with slightly convex or concave centre, frequently flat, diameter 5.9 - 8.3 μm, striae are double, rarely triple, in numbers of 14 - 16 in 10 μm. One central process is present. Spines pointy, small-scale, growing from each costa (Fig. 5 F).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
F7849DE942DC53DAABB276945D6B1C0C.taxon	distribution	Distribution. Stephanodiscus makarovae was observed downstream from Mykolaiv city in the Southern Bug River (Table 1). It was observed in the Dnipro River and its reservoirs, the Danube River and in the coastal area of the Black Sea (Genkal et al. 2009; Tsarenko et al. 2009; Genkal and Terenko 2014). As for general distribution, this taxon has only a few records around the world - Europe (Russia, Ukraine), Asia (Armenia, Russia), Africa (Egypt) (Kulikovskiy et al. 2016; Genkal et al. 2020).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
0444550A6D0955C9BD0BC0F684DADD0E.taxon	description	Morphological description. The frustule is disciform, valves flat or with slightly convex or concave centre, 8.8 - 9.1 μm in diameter, striae double to triple, numbering 10 in 10 μm (Fig. 5 G, H). A central process is present. The spines are short, growing from each rib (Figs 5 G, H, 6 A).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
0444550A6D0955C9BD0BC0F684DADD0E.taxon	distribution	Distribution. Stephanodiscus minutulus occurred at the Mykolaiv city and downstream the Southern Bug river sites (Table 1). This taxon is distributed over the entire territory of Ukraine, common for such rivers as the Dnipro with its reservoirs and tributaries, the rivers Dnister, Danube, Siverskyi Donets, estuaries of main rivers (Tsarenko et al. 2009). Concerning worldwide distribution, Stephanodiscus minutulus is a widespread taxon, recorded for Europe (i. e. Estonia, Finland, France, Germany, Great Britain, Hungary, Ireland, Moldova, Norway, Russia, Ukraine), Asia (Armenia, Georgia, Iran, Israel, Russia, Japan), North America (Canada, Greenland, USA) (Tsarenko et al. 2009; Kiss et al. 2012; Kulikovskiy et al. 2013; Genkal et al. 2020).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
75AAF112DFEB55EAA2C6FED25FCCF265.taxon	description	Morphological description. The frustule is low-cylindrical, valves are flat, 21.4 - 25.5 μm in diameter, central processes located on the valve ingroups, 6 marginal fultoportulae in 10 μm (Fig. 4 G).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
75AAF112DFEB55EAA2C6FED25FCCF265.taxon	distribution	Distribution. Thalassiosira faurii (Gasse) Hasle occurred near Mykolaiv city in the Southern Bug River (Table 1). This taxon was registered for the Dnipro River and its reservoirs, mouth of the Danube in the Black Sea (Maystrova et al. 2007; Roubeix et al. 2014). Worldwide distribution shows this species to occur in some European countries (Hungary, Russia), Asia (Russia), Africa (Ethiopia, Tanzania, Kenia, Kongo) (Tsarenko et al. 2009; Roubeix et al. 2014; Genkal et al. 2020).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
253E3A753E56591BA103B0980817E9A9.taxon	description	Morphological description. The frustule is cylindrical, valves approximately flat, 21.4 - 27.8 μm in diameter, in the middle of a valve 5 processes are located, 4 - 5 marginal fultoportulae in 10 μm, situated on the valve margin (Fig. 4 F). The rimoportula is short-necked with an elongated, compressed narrow lip usually perpendicular to the margin.	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
253E3A753E56591BA103B0980817E9A9.taxon	distribution	Distribution. Thalassiosira incerta was recorded near Mykolaiv city in the Southern Bug River (Table 1). For Ukrainian territory, there are few records from reservoirs of the Dnipro River and some estuaries of the Black Sea and coastal waters near Crimea (Tsarenko et al. 2009). This taxon is quite cosmopolitan, and distributed in the Boreal of Europe (Great Britain, Russia, Ukraine), Asia (Azerbaijan), North America (Canada, USA), Africa (Egypt); Aral, Black and Caspian Seas (Sims 1996; Kuo and Guo 2003; Okhapkin et al. 2016; Genkal et al. 2020).	en	Bilous, Olena P., Genkal, Sergey I., Zimmermann, Jonas, Kusber, Wolf-Henning, Jahn, Regine (2021): Centric diatom diversity in the lower part of the Southern Bug river (Ukraine): the transitional zone at Mykolaiv city. PhytoKeys 178: 31-69, DOI: http://dx.doi.org/10.3897/phytokeys.178.64426, URL: http://dx.doi.org/10.3897/phytokeys.178.64426
